Hair waving method and neutralizing compositions



United States Patent a Application September 23, 1952 Serial No. 311,162

6 Claims. (Cl. 132-7) No Drawing.

This invention relates to permanent Waving of human hair, andparticularly to materials, 'and hair waving methods employing'them, bywhich waves of improved quality may be obtained safely, conveniently andeconomically. The'method'is of the cold wave'type, and the materials arewell adapted to be sold and used as the so-called home kit, as well asprofessionally.

The present invention eifectively utilizes sulfite-type materials forcold waving, and a fundamental object of the invention is to overcomethose problems which heretofore have been regarded as insuperable to thecommercial acceptance of proposals to cold Wave hair by the use ofsulfite. Extensive practical experience with the sulfite coldwaves ofthe present invention and of the invention disclosed in our copendingpatent application Serial Number 311,161, filed concurrently herewith,has demonstrated that those problems have now been obviated.

This experience has also been adequate to show that the wave of thepresent invention effects a number of improvements over the only coldwaving procedure now in any significant use commerciallythe s'o-calledthio wave, using thioglycolate lotions. waves, the materials ofthe'present invention are substantially non-odorous and they greatlyreduce the hazards of irritation. The wave produced by the presentinvention is less susceptible to subsequent relaxation. The problem ofsusceptibility of hair to alkali degradation is obviated by the presentinvention by its retention of the hair in an acid environment ascontrasted with exposure to alkali for long periods of time, even amatter of hours in many instances, with the conventional thio wave. Thedanger of hair breakage is substantially reduced by this inventionbecause although the wave develops with speed comparable to that ofmercaptan-type lotions, yet if the exposure of the hair to the lotion isprolonged, the destruction so commonly experienced with mercaptanlotions does not take place.

Prior proposals to cold wave hair using sulfite type materials have beenunsuccessful for a number of reasons. Knowledge gained from our presentinvention demonstrates that one fundamental fault has been in attemptingto utilize, for sulfite type materials, the reaction mechanism of theconventional mercaptan or thio cold wave, as that reaction has heenunderstood. The simple reversibility of the widely used hot sulfitereaction appeared to justify the analogy, but'this, as will be shown, ismisleading. v I

Inasmuch as sulfite materials, like mercaptans, areire ducing agents,theaccepted practice of using oxidizing agents to reverse the processand rebuild the hair structure broken down by the mercaptan reducingagents, has prompted the use of oxidizing agents to restore hair reducedwith sulfite. However, directly 'co-ntrary to the mercaptan type coldwave, the coldreaction of sulfite uponlhair is not direct reduction offdisulfide, and the reaction of oxidizing agentsonIsulfiteqeducedhetirwill not rebuild the' original disulfide bonds in the keratin moleculebut will irreversibly form sulphone'byproducts characterized by hairthat is rubbery and waves that are limp and evanescent.

According to the present invention the acid sulfite relaxed hair keratinhas its disulfide bonds rebuilt by treatment with an aqueous solution ofhexamethylenetetra mine which operates, it is believed, to reverse thesulfite equilibrium reaction which reduced the hair, by forming" inertreactionv product with the acid sulfite, and also possibly by forming acomplex with the cysteine moiety of reduced hair. This reversal of theequilibrium reaction rebuilds the disulfide bonds to their original formin the hair keratin. i

In the discussion that follows, the polypeptide structure of which hairis composed is referred to as keratin and any reference to cystine,cysteine, disulfide bonds, or sulfhydryl groups will pertain to theexistence of these v groups in the keratin.

In contrast with thio The following equations illustrate the hairsoftening and rebuilding reactions:

Reducing step Intact hair Acid (cystine) sulfite Relaxed hairThiosulfate (cysteine) moletyhoi relaxed air Rebuilding step Relaxedhair Thiosuliate (cysteine) moiety of relaxed hair RSSR representsintact hair in which the cystine linkage between two polypeptide chainsis unbroken; the symbol SS- designates a disulfide bond of such acystine linkage. v

RSH represents relaxed hair, the SH delineating the mercaptan radical inthe cysteine moiety which results from the mercaptan reduction of thedisulfide linkage of keratin.

Hm is hexamethylenetetramine.

Me is a cation.

H is the acid sulfite anion. I

R--SSO Me is the Me salt of a thiosulfate'derivative of keratinresulting from the action of acid sulfite on the other sulfur of thebroken disulfide bond.

MeI-ISO .Hm is an inactive complex formed in the reversal withhexamethylenetetramine.

these lone mercaptan radicals are part of a solid material (the relaxedhair) they have limited mobility and very few of'such lone mercaptanradicals aresufiicientlyjnear to another mercaptan-radical to permittheir direct reoxidation to disulfide bonds. The great majorityof thesemercaptan radicals will, therefore, react with any applied. oxidizingagent irreversibly to yield sulfone and sulfonate terminal groups.instead of the reenforcing S-S- groups of intact hair.

This invention is predicated on our fundamental discovery that oxidizingagents cannot be utilized to reverse the reaction in the waving of hairat room temperature with acid sulfites.- This finding goes beyond theobservation that the introduction of an oxidizing agent to the systemdescribed in Equation (1 would oxidize the sulfhydryl groups in therelaxed hair as well as destroy the bisulfite on the left-hand side; ofthe equation. If this were all, we would expect to achieve onlyinefficient or partialreversal. InAactual fact we have found that noapparentreversal whatever takesplace when any common oxidizing agent(peroxide, bromate, iodatc, perborate, chlorite, etc.) is directlyapplied. to bisulfitereduced. hair..- Thecystine .content. of .the.hair. does not significantly. 'A,.load-elongation hysteresis loop madeon 'bisulfite-reduced fibers before and after oxidizing'treatment showsno, recoverywhatever. Since the acid sulfite constituent on theleft-handiside is unquestionably destroyed whenan oxidizing agent isintroduced,

it is most surprising that no detectable reversal. of the reaction canbe produced by thismeans.

Equation (2) illustratesthe reaction ofthe hexamethylene tetramine onrelaxed hair to cause the equilibrium of Equation (1) to shift tothe-left to restore the original disulfide bonds. However, this'reversalregenerates the MeHSO which had beenconsumed in the reducing step andthis'in turn reacts with more hexamethylenetetramine to becomeinactivated as a complex. The hexamethylenetetramine may also form acomplex with the cysteine which acts as an intermediate in the ultimatereversal. Theneutralizing reaction including'formation of any complexintermediates takes place rapidly upon the simple addition of aqueoushexamethylenetetramine to the relaxed hair.

, This hexarnethylenetetramine neutralization reaction is an equilibriumreaction so that although most of the reduced disulfide bonds arerebuilt by hexamethylene tetramine, some cannot be rebuilt in itspresence.' Accordingly, while not essential, it is highly desirable foroptimum effectiveness to complete'the destruction of the acidsulfite-which is present at equilibrium. For this purpose an oxidizingagent, properly selected and properly employed, is effective. We :havefound that if a slowacting loxidizing agent, such asa" soluble bromatesalt, is employed? 'the equilibrium bisulfite is effectively destroyed,and yet the oxidizing action is so slow in comparison with the rapidaction of the"hexan1eth'ylenetetramine that the slow acting oxidizingagent may be mixed with the hexainethylenetet'ramine withoutdangenofoxidation of the sulfhydryl group shown on the right-hand sideof Equation (1). However, if a fast actingbxidiz'ing agent, such asperoxide, is employed, having aspeed' of reaction comparable to .orgreater than thato'f the hexamethylenetetr'am'ine, the two materialsmust be usedin sequence to assure that the hexamethylenetetraminecompletes its reversal before the sulfhydryl group is oxidized to anon-bridging sidechain. J

The hexamethylenetetraminemay form-a complex with the cysteine moietyofreduced hair which tends to pro tect this readilyvoxidizable. substanceagainst premature oxidation. This appears to be the most probable reasonwhy hexamethylenetetramine is effective to reverse the reaction'even inthe presence of a slow-acting oxidizing agent.

Proceeding accordingto the present invention, the hair is treated withan acid sulfiteibisulfite) relaxing solution which may be varied both asto its pH value and its normality. depending upon a number of factors.The

ultimate objective is a lotioncontaining an adequate concentration ofacid sulfite ions in solution to effect the relaxation in a reasonablyshort time atroom temperature, and that concentration will vary bothwith pH and normality. Solutions within a preferred pH range of 6,0 to6.6 and a preferred strength ofl to 2.5 N will relax normal hairadequately in a preferred time range of ten to seventy-five minutes.Within these ranges, the lower the pH and the higher the normality thehigher will be the acid sulfite ion concentration and the shorter therelaxing time required.- A pH as low as 5.5 may be employed but thesolution should not have a lower pH value than 5.5 as it would then tendto evolve intolerable amounts of S0 a gas which has a degrading andbleaching effect on the hair and an objectionable odor. A pH value ashigh as 7.5 is the practical upper limit. If the total titer (sulfiteplus bisulfite) exceeds 3.0,N a pH as high as 8 could be used but onlyunder conditions seldom resorted to in' practice, such as dipping thehair in the lotion; With the lowerrange of pH values specified above theconcentration of the acid sulfite may be as low as 0.5 ,N.

These ranges of values afford the wide flexibility of treatmentnecessary to accommodate our invention to the specific requirements ofgiven conditions of use. Thus non-professional home use can involve muchlonger processing times than could be tolerated economically by theprofessional beauty operator and time ranges of relaxing treatment fromabout five minutes to about two hours or even more are readilyobtainable within the scope of the present invention.

The hair may be first wound upon rods and then wetted with acidsulfiteto relax it, or it-. may be first wetted with acid sulfite and thenwound, either sequence being' completed prior.- to" setting byneutralizing. In any event the hairis lefton the rods. in contact withthe acid sulfite for-a suitable period of time'b efore neutralization..1 3

After relaxation with acid sulfite of controlled pH, the hair, whilestilliwo'und on rods, is treated with an aqueous solution ofhexamethylenetetramine to set the hair by rebuildingv the disulfide.bonds.which.,have been broken by the acid sulfite.-

The hexam'ethylenetetramine is generally applied to the hair as anaqueous solution having a pH range of about 4 to 6.5, preferably 4.5 to5.5. Theactivity of the hexamethylenetetramine may be varied within thepH. range given, the lower pH tending to speed up and the higher pHtending to retard its rapid acting'etfect to -r'eversc the reaction. j

Where the hexarnethylenetetramine is used in solution with a slow-actingoxidizing agent, the agent is; preferably a bromate of an alkali metal,such as sodium, potassium, or lithium, but the corresponding chloratesmay be substituted for bromates with the obvious disadvantages ofthehazards involved in their handling. Where hexamethylenetetramine isfirst applied independently of an oxidizing agent, an oxidizing agentmay be subsequently applied. Such independently applied oxidizing agentmay be of any character, slow or fast acting as desired. For thispurpose, any known oxidizing agents may be used in any quantitysufficient to oxidize and destroy the bisulfite not complexed with thehexamethylenetetramine. It is not absolutely necessary to use anoxidation agent at all, either in combination with thehexamethylenetetramine or following the hexamethylenetetramine, asthereversal in any event issu'bstantially completed without it. The use ofan oxidizing agent is in the nature of an optional but preferredafter-treatment to destroy-any residual bisulfite present, such residueshaving obviously a hair softening effect in .acid'environment. Thisafterrtrea'tmentcharacter of the oxidation is not changed by thefactthatby the present invention we have been able to apply the.hexamethylenetetramineand a slow oxidizing agent in the same solution.If no oxidizing agent is used, copious rinsing with water to removeresidual bisulfite and bisulfite-hexamethylenetetramine complexes -isdesirable. The reversal and rebuilding is completed afterexpQSLire tohexamethvlenetetrarnine for a period of about 8 utes or longersuch as upto about 30 minutes, generally depending on the efiiciency of thepenetration of the wound tress by the hexamethylenetetramine. Theoxidation of bisulfite and its complexes, if by a separate solution maybe performed after the hair has been unwound, because the wave has beensubstantially set as soon as adequately penetrated by thehexamethylenetetramine solution. e

Other after-treatments are sometimes desirable. When the hair is rebuiltby an acid hexamethylenetetramine solution containing a slow oxidizingagent, the hair will, of course, remain acid in the pH range abovestated, so that after processing, the hair need merely be unwound fromthe curling rods and rinsed with water, or, if desired, with anyconventional after treatment rinse having no chemical action. Where thehair is treated first with hexamethylenetetramine alone, thesubsequently applied oxidizing agent is also preferably acid but may bealkaline, such as an alkali metal bromate in a pH range from 8 to 1 0,in which event a final acid rinse may desirably be employed to restorethe hair to its natural acid pH. All such aftertreatments, including anyoxidizing agent, may be applied to either wound or unwound tresses.

Acid sulfites of the alkali metals, ammonia or organic amines areeffective for relaxing the hair. Thus, useful examples include sodium,potassium or ammonium acid sulfite, simple mono, di-, or tri-alkylamines such as the methyl, ethyl, propyl or butyl amines, alkanol aminessuch as diethanol amine, cyclic amines, such as morpholine, piperidine,and piperazine, as well as other basicacid sulfite forming organicsubstances such as guanidine and formamidine.

Acid sulfites are readily obtainable in a pH range below 5.5 by passing,as by bubbling, S gas through a relatively concentrated solution of awater soluble alkali or alkaline salt having a cation corresponding tothe desired cation of the acid sulfite. then be diluted with to 40% ofalcohol which brings the apparent pH int-o the preferred range of 6.0 to6.6. This dilution of the concentrate with 5 to 40% alcohol also may besuch as to bring the concentration of the sulfite to the range of 0.5 to3.0 normal, or the preferred range of 1 to 2.5 normal.

Commercial sulfite solutions thus produced are usually made up fromordinary natural commercial waters, such as tap or spring water,whichcommonly contain trace quantities of the multi-valent ions of iron,cobalt, copper or manganese. In the presence of oxygen, such ions intrace quantities tend to accelerate oxidation of sulfite in storage soas rapidly to destroy the sulfite in partially filled bottles after theyhave been opened for use. For this reason the acid sulfite is preferablyused in combination with a metal sequestering agent. Such a metalsequestering agent is of the nature of an ammonium or alkali metal saltof a polybasic acid compound. Such polybasic acid compound may be one ofthe soluble salts of the simple fruit acids such as citric, or tartaricacid or homologues thereof, or salts of succinic, gluconic, glutaric,maleic, or oxalic acid, but preferably are amino derivatives ofpolycarboxylic acids having the structure R'N(RCOOl\ le) wherein Me is asoluble cation, generally ammonium or any alkali metal such as sodium orpotassium; R is a simple lower alkylene such as methylene, ethylene,propylene, etc.; and R is hydrogen, lower alkyl or amino lower alkylene,of Which the alkyl or alkylene has 1 to 3 carbon atoms and the aminogroup of which may 'be further substituted with metallic acyl groups ofthis formula. Thus, such compounds as trisodium triacetic acid amine,the tetra sodium salt of tetra acetic acid ethylene diamine, and higherpolyamines are useful examples. Compounds of this character are knowncommercially as Nullapons, Versenes and Sequestrenes. The metal ionsequestering agent is generally used in minor quantities correspondinggenerally to the quantity of metallic ion to be sequestered and Theconcentrated solution may will approximately range from .001 to 0.5% ofthe solution. 1

' The hexamethylenetetramine solution is a simple solution in water. Theupper quantity limit of the hexamethylenetetramine is not critical. Forthe purposes of practical economy it is usually less than 5 molar and isusually made up in concentrations of .05 to 3.5 molar as indicated abovepreferably in the rangeof .15 to 1.0 M and in a pH range of 4.5 to 5.5.When an oxidixing agent is used, it may be made up with thehexamethylenetetramine in the same water solution if a slow-actingoxidizing agent such as an alkali bromate salt is selected. Suchoxidizing salt is usually used in proportion of /2 to 4%. Alternatively,any oxidizing salt such as alkal metal bromate, iodate, chlorate,hypochlorite, perborate or acids such as perboric acid monohydrate, orordinary hydrogen peroxide, may be used separately and subsequent to thehexamethylen-etetramine treatment. The hexamethylenetetramine solutionalone or combined with a slow-acting oxidizing agent, or the solution ofoxidizing agent to be used subsequently, may further contain a monobasicsodium phosphate as a bufiering agent, or other acidic buffering saltsmay be used.

Various common additives useful in hair waving lotions further may beincluded in either or both the acid sulfite keratin relaxing solution orthe hexamethylenetetramine solution. For example, such materials aswetting agents may be used, preferably of a non-ionic type such as thealkyl phenoxy polyethoxy or other polyalkylene oxide derivatives, butanionic and cationic types may be used alternatively if desired, thewetting agent being present in minor quantities ranging from about 0.1to about 3%. The lotions may further contain opacifying agents, such asoils or insoluble resinous materials such as polymerized methylinethacrylate together with suitable dispersing or emulsifying agents,to render the solutions opaque, and the solutions may also containcoloring agents, perfumes, etc.- to make the product attractive. Theseadditives, opacifiers, perfumes and colorings are usually used in suchminor quantities as from about 0.001 to about 1%.

The chemicals employed in accordance with the present invention areharmless when used in the prescribed manner and they are superior in thewave they produce. A minimum of control is required so that they areexcellently adapted for home or nonprofessional use. For this purpose,the chemical solutions, i. e., the hair relaxing lotion and the settinglotion, the two lotions to be applied in sequence to the hair andcooperatively effective for purposes of first relaxing the hair so thatit will readily take the curl, and then restoring the curled hair to itsoriginal chemical structure so that the wave becomes permanent, may bemade up in a home kit.

Some of the compositions may be packaged as dry powder for ultimateaddition to a controlled quantity of water just prior to use. It ispossible also to furnish some of the kit components as solutions andothers as dry powders, depending somewhat upon advantages to be gainedin greater storage stability of one form as contrasted with the other,or reduced shipping costs. Thus, both hexamethylenetetramine crystalsand bromate salts are sometimes preferably packaged as dry powders withbulfers, etc. to produce the desired acidity when dissolved in water foruse. When the slow acting oxidizing agent and hexamethylenetetramine areto be combined in a single solution, either may be packaged dry with thecontrolling acid buffer distributed in either for optimum stability togive the desired acidity when combined.

The following examples illustrate the practice of this invention ExampleI.Preparation of keratin relaxing lotiori Sulfur dioxide gas is bubbledat room temperature into a 30% solution in water, of guanidine carbonateto form an 'acid solution of guanidine' blsulfite having a pH of aboutS.8. The solution is filtered,if'necessary,' torernove suspendedimpurities. The solution is then diluted to approximately double itsvolume with water, after which 10% N-propyl alcohol is added. Thisquantity of alcohol will raise the apparent pH of the solution toapproximately 6.1. To this solution is added 1% of a metal sequesteringagent consisting of sodium 'tri-acetic acid amine. Thereafter, a wettingagent," Triton X-100, an alkyl phenoxy polyethoxy ethanol, is added inquantity of A concentrated suspension of methyl methacrylate polymer,suspended in water, is added sufficient in quantity to cream and bodythe lotion, about 0.5%. Minor quantities of perfume and color,sufiicient to render the product attractive, are further added.

Example II Ammonium acid sulfite is dissolved in water or may be formedin an aqueuos solution from ammonium carbonate and sulfur dioxide in amanner similar to that described in Example I, and diluted with ethylalcohol to form a 15% alcoholic solution of the ammonium acid sulfitecontained therein in concentration of 1 normal. To this is added .25% ofa wetting agent consisting of Triton X-100, 5% of a methyl methacrylatepolymer dispersion in water to imparttothe solut ion a creamy appearanceand also sufficient perfume and dye to render the product attractive.Additionally, if the solution is made up from tap water, 1% of sodiumtriacetic acid amine will be added as a 'sequestrant. In this example,the final pH of the solution will be approximately 6.2.

Example III Guanidine acid sulfite formed as described in Example I andcontaining this acid sulfite in concentration of 2.5 normal and havingan isopropyl alcohol content of 30% with further quantity of A% ofTriton X-100, is adjusted to pH 7.3 with guanidine carbonates.

Example IV Guanidine acid sulfite prepared as described in Example I,but having a pH of 6.0 and containing 40% of alcohol, the total acidsulfite being adjusted to .25 N, is made up with additional quantitiesof a non-ionic wetting agent, a creaming agent, and minor quantities ofperfume and color, as described in Example I, to form an effectivesoftening agent for relaxing the hair.

Other examples follow:

v Example V Guanidine carbonate; 27lbs. Nullapon Bnm; 1.065 lbs. Sulfurdioxi de 14 lbs. (approx) Isoproply alcohol (91% 2 gals., 91 fi. oz.Alkyl phenol 'polyethoxy ethanol 1 lb. Perfume .i. -l a..;;;.. 0.12 lb.Water 14 gals, 113 fl. oz. Adjust with S or giianidine carbonate to pH6.6. 7

Example VI Ammonium carbonate (monohydrate) 16.4 lbs. Versene -'0.66 lb.Sulfur dioxide 14 lbs. (approx) Isopropyl alcohol (91%) 2 gals, 91 fl.oz. Alkyl phenol polyethoxy ethanol 1lb. Perfume 0.18 lb. I Water l4gals, 1 13 fl. oz.

TExample VIIQ-Nutializer solution a 35 grams of hexamethylenetetramineare dissolved in water to form a .25 molar solution. The pH of thesolution, at first approximately neutral, isacidified by tracequantities of acetic acid or monoba'sic sodium acid phosphate added toadjustjthepH toapproximately 5.5.. The solution is then ready for use'as a neutralizing solution i 8 and may be used directly alone, or itsapplication may be followed by treating the hair with an oxidizingagent,as s'et'forthin Example .VIII or IX. 7 2 Example VilI.--Oxidizingsolution :A 16% by weight solution of sodium bromate is made up in watercontaining additionally [7% of a buffer consisting of trisodiumphosphate dodecahydrate and 7.7% of monosodium dihydrogen phosphatemonohydrate, 3% of anytypical wetting agent in solution, 2% of anopacifier, i. e.', a concentrated suspension in water of polymethylmethacrylate, perfume 0.2%, and water approximately 68.4%. The pH of thesolution is approximately 4.8. This solution is normally diluted fourtimes with water'prior to use and is of a suitable concentration forsupply with a home kit adapted to be further diluted by the user.

' Example IX Example X.--Combined hexamethylenetetramineoxidizersolution 14.0 grams of hexamethylenetetramine is dissolved in one quartof water, and the pH of the solution is adjusted to 5.5 by addition of asmall quantity of monosodium acid phosphate. A package is made upconsisting of a powdered mixture of 16.0 grams of sodium bromate and 15grams of monosodium phosphate, the total contents of the package beingdissolved in the quart of hexamethylenetetramine just prior to use as amu tralizer. V

The hexamethylenetetramine solution may further contain a nonionic,cationic or anionic wetting agent such as Triton X-100, Tergitol orother well known wetting agents, of which the alkyl phenoxy polyalkyleneoxide alkanols are typical for the non-ionic type, quaternary ammoniumchlorides such as benzyl higher alkyl dimethyl ammonium chloride knownas Zephiran is typical of the cationic type, and sodium lauryl sulfateor a mixture of alkali metal sulfated alcohols predominating in sodiumlauryl sulfate are typical of the anionic type, of which the followingis an example:

Example XI 30 grams of hexamethylenetetramine and 15 grams of succinicacid are dissolved in one quart of water. There is further added .1% byweight of Triton X-lOO, 2% by volume of a 20% weight suspension ofpolymethyl methacrylate in water and traces, q. s. to make the productattractive, of a coloring agent and a perfume.

Example XlI.-Typical hair waving procedure with the chemicals hereof Thesolution of Example I is combed into dry hair, or hair which has beenpreviously dampened, as by preliminary shampooing and removing of mostof the free moisture, to thoroughly distribute the waving lotion on thehair. The wet hair is then wound upon conventional curling rods, and thehair allowed to process in the curled form for approximately 30 minutes.Thereafter, the softened hair on the curling rods is treated bymoistening with the solution of Example VII by thoroughly saturating thewound hair therewith and allowing to stand for approximately 15 minutes.As indicated above, the setting of the curl is largely a mater ofobtaining thorough penetration and, depending upon the type of rod, thetime may vary for a greater .or lesser period. By this treatment thehair has become permanently set and may be unwound from the rods. Thehair may be washed to remove the chemicals or may be treated with anoxidizing agent as set forth in Example VIII or IX to destroyresidualsulfite.

9 Example XIII.-Setting procedure After the hair has been relaxed for asufiicient period, as set forth in Example XII, by processing with acidsulfite of solutions prepared as set forth in any of Examples I throughVI, it may be set by a combined solution of hexamethylenetetramine withan oxidizing agent. Thus, the hair may be wet in a manner to penetratethoroughly the tress with a solution as set forth in Example X. Afterstanding for at least eight minutes, and preferably about 15 minutes tobe certain that the neutralizing solution thoroughly penetrates theWound tress, it may be unwound from the curling rod. The hair has beenset with the hexamethylenetetramine and the residual sulfite has beenremoved by oxidation. Hence, no washing of the hair is necessary,although the hair may be washed, if desired, to remove residual salts.

Many other useful examples will occur to the man skilled in the art oncethe'principle of our invention is understood. Although the theoreticalexplanation of the mode of operation of various hair waving treatmentsgiven here is based on exhaustive research and is believed to be sound,our'invention is, of course, not to be circumscribed by any suchstatements of theory.

We claim:

1. A method of cold waving hair on the human head comprising softeningthe keratin of the hair at room temperature by applying thereto about0.5 to about 3.0 N acid sulfite solution having a pH range from about5.5 to about 7.5, and then setting the softened hair while deformed uponcurling rods by applying thereto an aqueous acidic solution ofhexamethylenetetramine.

2. A method of cold waving air on the human head comprising wetting thehair on the human head with about 0.5 to about 3.0 N acid sulfitesolution having a pH range from about 5.5 to about 7.5 to soften thesame at room temperature, and then setting the hair while deformed uponcurling rods with a neutralizing solution comprising an aqueous acidicsolution of hexamethylenetetramine and a slow acting oxidizing agentselected from the group consisting of alkali metal bromate and alkalimetal chlorate.

3. A method of cold waving hair on the human head comprising wetting thehair on the human head with about 0.5 to about 3.0 N acid sulfitesolution having a pH in the range of about 5.5 to about 7.5 to softenthe same at room temperature, and then neutralizing the 10 softened hairwhile deformed upon curling rods, first with an aqueous solution ofhexamethylenetetramine, and then with an aqueous solution of anoxidizing agent.

4. A method of cold waving hair on the human head comprising wetting thehair on the human head with an aqueous alcoholic solution of about 0.5to about 3.0 N acid sulfite salt selected from the group consisting ofalkali metal, ammonium, organic amino and organic amido acid sulfites inthe pH range of 6.0 to 6.6 to soften the same at room temperature, andthen neutralizing the softened hair while deformed upon curling rodswith an aqueous acidic solution of hexamethylenetetramine and a slowacting oxidizing agent selected from the group consisting of alkalimetal bromate and alkali metal chlorate; said solution being buffered inthe pH range of about 4 to 6.5.

5. A neutralizing solution for the setting of hair on the human headwhich has been softened with an acid sulfite in the waving thereofcomprising about a 0.15 to 3.5 molar aqueous solution in the pH range ofabout 4 to 6.5 of hexamethylenetetramine and a slow acting oxidizingagent selected from the group consisting of alkali metal bromate, andalkali metal chlorate.

6. A dry composition adapted in aqueous solution for setting of hair onthe human head which has been softened with an acid sulphite in the coldwaving thereof, comprising a mixture of hexamethylenetetramine, a slowacting oxidizing agent selected from the group consisting of alkalimetal bromate and alkali metal chlorate, and a buflering agent adaptedto maintain said salt mixture in aqueous solution at a pH in the rangeof about 4 to 6.5

References Cited in the file of this patent UNITED STATES PATENTS1,008,249 Elsaesser Nov. 7, 1911 2,351,718 Speakman June 20, 19442,400,377 Speakman May 14, 1946 2,437,965 Michaels Mar. 16, 19482,508,713 Harris May 23, 1950 FOREIGN PATENTS 494,927 Great Britain Nov.3, 1938 697,634 Germany Oct. 18, 1940 552,285 Great Britain Mar. 31,1943 534,838 Germany Sept. 25, 1931 928,871 France Dec. 10, 1947

1. A METHOD OF COLD WAVING HAIR ON THE HUMAN HEAD COMPRISING SOFTENINGTHE KERATIN OF THE HAIR AT ROOM TEMPERATURE BY APPLYING THERETO ABOUT0.5 TO ABOUT 3.0 N ACID SULFITE SOLUTION HAVING A PH RANGE FROM ABOUT5.5 TO ABOUT 7.5, AND THEN SETTING THE SOFTENED HAIR WHILE DEFORMED UPONCURLING RODS BY APPLYING THERETO AN AQUEOUS ACIDIC SOLUTION OFHEXAMETHYLENETETRAMINE.